Trait datafusion::logical_plan::ExprRewriter

pub trait ExprRewriter<E = Expr>where
    E: ExprRewritable,{
    fn mutate(&mut self, expr: E) -> Result<E, DataFusionError>;

    fn pre_visit(
        &mut self,
        _expr: &E
    ) -> Result<RewriteRecursion, DataFusionError> { ... }
}

Trait for potentially recursively rewriting an Expr expression tree. When passed to Expr::rewrite, ExpressionVisitor::mutate is invoked recursively on all nodes of an expression tree. See the comments on Expr::rewrite for details on its use

Required Methods

fn mutate(&mut self, expr: E) -> Result<E, DataFusionError>

Invoked after all children of expr have been mutated and returns a potentially modified expr.

Provided Methods

fn pre_visit(&mut self, _expr: &E) -> Result<RewriteRecursion, DataFusionError>

Invoked before any children of expr are rewritten / visited. Default implementation returns Ok(RewriteRecursion::Continue)

Implementations on Foreign Types

impl<'a> ExprRewriter<Expr> for ConstEvaluator<'a>

fn pre_visit(&mut self, expr: &Expr) -> Result<RewriteRecursion, DataFusionError>

fn mutate(&mut self, expr: Expr) -> Result<Expr, DataFusionError>

Implementors